1. Field of the invention
The invention relates to a tool for removing balance weights attached to the periphery of a rotor wheel of a turbine.
The invention is applicable to the removal of balance weights from any turbine requiring maintenance or rebalancing of the turbine on the engine bed, the turbine remaining fitted with its exhaust nozzle, and is
Particularly applicable in the field of avionics to turbojet engines requiring regular maintenance, for which the intervention time must be as short as possible.
2. Summary of the Prior Art
The rotor of a turboshaft engine rotates at speeds such that the slightest imbalance may lead to extremely harmful vibrations. To prevent such vibrations it is therefore necessary to balance the rotor. Generally, thin balance weights are crimped in place at the head of a blade. In the case of the low-pressure turbine of CFM56 engines, for example, small balance weights are placed between two blade platforms at the periphery of the fourth stage wheel.
When attending to an aircraft engine in the course of maintenance, it is sometimes necessary to rebalance the turbine without any particular disassembly. For this purpose, a tool is used for placing and crimping the balance weights between two blades, on the inside of the peripheral rim formed by the heads of the rotor blades, the tool being introduced through a nozzle.
While the placing and crimping of such balance weights through the nozzles of the turboshaft engine is relatively easy, this is not the case for the reverse operation, which involves unseating and removing the weights from the peripheral rim, as the risk of dropping a weight in the engine during this operation is considerably greater. When a balance weight which has just been unseated falls between two stages of the turbine, there is no other option but to dismantle the nozzle in order to recover the weight.
A tool exists which permits the placing and crimping of weights on the periphery of a turbine wheel without having to dismantle the nozzle, but at present there is no tool able to perform the reverse operation in a sufficiently reliable manner. Accordingly, it is usual for the nozzle to be dismantled to carry out the removal of balance weights.